Rapid Proton Transfer as Cause of an Unusually Large Neighboring Group Effect

An acceleration of the transesterification of arylboronates by a factor of about 109 can be achieved by introduction of nitrogen-containing substituents or moieties into phenylboronic acid esters. Examples are aryl  o-(dimethylaminomethyl)phenyl, o-(dimethylamino)phenyl, 8-quinolyl. Arylboronic acids thus become available which are suitable, after immobilization, for a very rapid chromatographic separation of diols.